package week5;

import java.util.Scanner;

public class q2 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入圆的半径： ");
        double pi = 3.14;
        double r = sc.nextDouble();
        double area = pi * r * r;
        System.out.println("半径为"+ r +"的圆的面积为：" + area);
    }
}
